The way you can figure this out is by looking at which ones multiply to be 30, but add to be -1. If you were to make a list of what multiplies to be 30, you’d probably do:
30 • 1 = 30 10 • 3 = 30 2 • 15 = 30 5 • 6 = 30
In this case, the best possible answer would be “5 • 6 = 30.” Therefore, you would get:
(x 5)(x 6)
Now, you would have to determine what makes -1. In this case, the answer would be to put a “-“ for 6 and a “+” for 5 because -6 + 5 make -1.
(If you’re still unsure, you can FOIL what you factored.)
